1. Field
The present invention relates to an electric home appliance having a drain function and a method of controlling the same, and more particularly to an electric home appliance having a drain function to more effectively perform a drain operation, and a method for controlling the same.
2. Description of the Related Art
Generally, an electric home appliance having a drain function may be a washing machine to wash laundry, such as clothes and a dishwasher, to wash dishes. The washing machine includes a dehydration process after performing a washing process, or a drain process drain water of a water tub before entering the dehydration process after a rinsing process. The dishwasher includes the rinsing process after the washing process or drains the water during a drain time of the next rinsing process.
The above-mentioned electric home appliance equipped with the drain function includes a drain passage and a drain apparatus (e.g., a drain pump) to drain the water from the water tub, so that the drain operation is quickly and easily performed.
The drain operation of the above-mentioned electric home appliance including the drain apparatus will hereinafter be described. Referring to FIG. 1, if a drain pump is switched on according to a series of prescribed steps at operation 1, water is drained from the home appliance, so that a water level begins to be lowered. In this case, the lowering water-level is detected at operation 3, and it is determined whether a current water level reaches a predetermined water level (also called a reset water-level) indicating the drain completion at operation 5.
If the water level of the home appliance does not reach the predetermined water level indicating the drain completion, a controller of the home appliance returns to operation 1 to continuously switch on the drain pump, so that the drain operation is continuously performed until the drain operation is completed. If the water level of the home appliance reaches the predetermined water level indicating the drain completion, the controller switches off the drain pump to finish draining the water at operation 7.
As shown in FIG. 2, according to the conventional home appliance equipped with the drain function, if the drain process starts operating by an ON-status drain pump, the drain pump is continuously operated until a current water level reaches a drain-completion water level. This operation is hereinafter referred to as a continuous drain operation.
The above-mentioned continuous drain operation can be easily performed under general situations. However, if the draining water-level starts increasing according to installation conditions (e.g., a draining height) of the home appliance, the possibility of generating cavitation caused by an air space (or air gap) of a drain-pump housing and the increased water pressure of residual water increases. If the cavitation occurs, the conventional home appliance cannot substantially drain the water during a predetermined time although the drain pump is continuously operated, so that an operation time of the drain pump (i.e., a draining time) becomes longer.